When sailing off the wind, sometimes the top of the jib starts to flap, this gets worse with every flap and starts to shake the mast quiet violently.

How do I stop it ???

Paul Burton.

Parker 235/ 40 Lady Penelope...

My Genoa leech stopped flogging when I put a little tension in the leech line. You should be able to squeeze the tension up to the top where it seems to be needed most in your case, like threading elastic into nickers. (no, I haven't done this, my mum used to though, before the throw away days)

Mike Edwards

Seal 28 "Aztec"

I had a similar problem with the top of my main sail, the leech started to flap just below the top batten. I tightened the leech chord a little bit and it stopped it, so I think Mike's advise will work fine.

Graham Ebb

235/25 Blue Jazz

Did tightening the leech line stop the flogging?

I had some fluttering with the jib eased sailing off wind.I rigged a Barton snatch block each side running the contol line through the loop at the base of the forward stachion and back to a cleat in the cockpit.I use the same blocks for running down wind with the jib and a whisker pole.No fluttering and more speed!

Nick Bett. "Last Orders"